Oscillation generator



Filed Oct. 18, 1933 2 Sheets-Sheet l INVENTOR JAMES N.WH\TAKER ATTORNEY .1. N. WHITAKER 2,103,655

05 C ILLAT ION GENERATOR Dec. 28, 1937.

Filed Oct. 18, 1935 g Sheets-Sheet 2 1 aura/r INVENTOR 7 JAMES N.WH\TAKER ATTORNEY Patented Dec. 28, 1937 v UNITED STATES PATENT OFFICE OSCILLATION GENERATOR of Delaware Application October 1a, 1933, Serial No. 694,016

9 Claims.

My present invention relates to multi-electrode tube oscillation generators and has as its object the provision of improved circuits for causing the production of stabilized oscillations with tubes having a multiplicity of grids.

A further object of my present invention is to provide an improved multiple grid tube oscillation generator utilizing a plurality of regenerative systems operating upon the common electron stream within the tube as a consequence of which increased power output and stability ensues.

While I have definedfmy invention with particularity in the appended claims, its structural organization as well as mode of operation may the accompanying drawings wherein;

- Figures 1 to 4 inclusive are wiring diagrams of circuits incorporating theprinciples of my present invention.

Referring in detail to the drawings and turning in particular to Figure 1, a multi-grid tube, electron discharge device or vacuum tube T is provided with two regeneratively connected oscillation generating systems. One system comprises a piezo-electric crystal I connected between grid 4 and cathode 3 and the tunable circuit 1 connected between the intermediate grid 5 and the cathode 3. The grid 4 may be termed a first electrode or it may be termed a grid adjacent the cathode 3. The intermediate grid 5' may be termed a second grid or a control electrode. The second regenerative system comprises the parallel tuned circuit 8 regeneratively coupling together theplate or anode 6.:and the grid electrode H1 35 adjacent the anode 6, which adjacent grid may be termed a third grid or control electrode. Bias for the grid electrode 4 is supplied throughthe choke coil battery arrangement 2, bias for the third grid III is maintained by the action of condenser and resistance l2 and suitable positive operating potentials are applied to the grid'5 and plate 6 through leads and 22 respectively.

Inthe operation of the system shown in Figure 1, because of interelectrode capacity between grid 5 and grid 4, oscillations are set up in circuit 1 at a, frequency corresponding to the natural frequency of the crystal l. These'constant frequency oscillations look into step the, oscillations generated in the tunedcircuit 8, which, as illus- 50 trated, forms, with the plate electrode, grid I 0 and cathode 3, an independent regenerative oscillating system. The plate 6 and grid |0 fluctuate 180 degrees out of phase because of their diametrically opposite connection to the tuned circuit 8. The midpoint oranlntermediate pointon best be understood by referring specifically to the tuned circuit 8 is maintained at filament cathode or ground potential, with respect to alternating currents, through the action of bypassing condensers 9, 2|. Tuned circuit 8 may feed any suitable output circuit as indicated diagrammaticallyand may be tuned to the same frequency as circuit 1 or the crystal I or may be tuned to some harmonic or sub-harmonic of the operating frequency of crystal I. Rather than use a piezo-electric crystal as a source of controlling voltages, any constant frequency source may be connected to points X, X indicated. If such a controlling frequency source is so connected to the points marked X, circuit 1 may be tuned to the same, to a multiple, or to some submultiple of the controlling frequency, and similarly circuit 8 may be tuned to the same frequency as the controlling frequency applied to points X to some harmonic thereof or to some sub-harmonic thereof. 7 20 The arrangement shown in Figure 2 differs from the system shown in Figure 1 in that the regenerative system including the plate 6 and grid l0 includes an additional tuned circuit l3 and also by the fact that bias for the grid I0 'is obtainedby the parallel combination of the grid leak l2 and condenser II. If desired, the inductance coils of the circuits l3 and 8 may be coupled together or isolated. In the latter event, regenerative action takes place by virtue of the 0 interelectrode capacity between the plate 6 and the grid Ill. All of the remarks made in connection with the system shown in Figure 1 as regards the tunings of the various circuits and the application of the controlling frequency at points X, X, apply with equal force to the system-shown in Figure 2.

The system shown in Figure 3 differs from the arrangement shown in Figure 1 in that the first regenerative system of Figure 1 including the 40 crystal has been replaced by tuned circuit 3| and also by the fact that the grid 4 is biased by the action of a grid leak and condenser arrangement 42. As before, the circuit 8 may be tuned to the same frequency as circuit 3| but preferably to some harmonic or to some sub-harmonic thereof.

In the system shown in Figure 4, the regenerative system includingtuned circuit 3| of Figure 2 has been combined with the double tuned circuit system I3, 8 of Figure 2. As before, the coils of tuned circuits I3, 8 may be inductively coupled together if desired or may be isolated. Also, in the arrangements shown in Figures 3 and 4, the circuit 3| may be dispensed with'and the regenera tive system utilizing two tuned circuits such as 3,

8 may be provided. In that case a parallel tuned. circuit would be connected between the grid 4 and the cathode 3 and another parallel tuned circuit would be connected between the grid 5 and the cathode 3. The tunings of the circuits within each regeneratively connected system should be alike and the tunings of the different regenerative systems may be alike or bear some harmonic relation to each other.

Having thus described my invention, what I claim is:

l. A generator comprising an electron discharge tube having an anode, a cathode, a first grid, a second grid and a third grid, a primary oscillation generating means including a piezoelectric crystal and a tuned circuit regeneratively connecting together said cathode, first grid and second grid, said tuned circuit being tuned to the crystal frequency, a secondary oscillation generating means including a biasing device interposed between the third grid and the cathode and including a tuned circuit regeneratively connecting together said third grid, anode and cathode and means operative by virtue of the coupling action of the electron stream between the second and third grids for maintaining the oscillations of the secondary generating means in step with those of the primary generating means.

2. Apparatus as claimed in claim 1 characterized by the fact that the tuned circuit regeneratively connecting together said anode third grid and cathode is tuned to a frequency harmonically related to that of the tuned circuit connected between said second grid and cathode.

3. In combination, a multi-electrode tube having a plate, a cathode, a first grid, a second grid, and a third grid, a piezo-electric crystal and a tuned circuit regeneratively connecting together said cathode, first grid and second grid, a tuned circuit regeneratively connecting together said anode, third grid and cathode, said last mentioned tuned circuit being tuned to a frequency harmonically related to that of said piezo-electric crystal, and means including a bias resistor interposed between the third grid and the cathode for causing oscillations to be self-sustained in the last mentioned tuned circuit.

4. An oscillation generator comprising a multielectrode tube having an anode, a cathode, a first grid, a second grid and a third grid, means including a tuned circuit for regeneratively connecting together said cathode, first grid and second grid, means including a tuned circuit regeneratively connecting together said anode said cathode and third grid, said last mentioned tuned circuit being tuned to a frequency harmonically related to that of said first mentioned tuned circuit, and means for producing self-sustained oscillations of the harmonic frequency in the last mentioned tuned circuit, said means comprising a biasing device interposed between the third grid and the cathode.

5. An oscillation generator comprising an electron discharge tube having a cathode, an anode, an inner grid nearest the. cathode, an intermediate grid and an outer grid nearest the anode, means including a piezo-electric device in circuit between the cathode and the inner grid for controlling the frequency of oscillations generated by capacitive interelectrode feed-back in said tube, a circuit tuned to the frequency of the oscillations so generated, said circuit interconnecting the intermediate grid and the cathode, means including an outer grid biasing device and a resonant circuit connected between the anode, the cathode and the outer grid as to permit of generating selfsustained oscillations therein, whereby the alternating potentials developed on said anode and on said outer grid are contra-phasal, while an intermediate point in said resonant circuit is maintained at substantially the same alternating current potential as that of the cathode, and means including a structure. for producing an electron stream between the intermediate grid and the outer grid thereby to maintain the oscillations of said resonant circuit in step with the piezo-electrically controlled oscillations.

6. A device in accordance with claim 5 and further characterized by the provision of a plurality of tuned tank-circuits in series between the anode and the outer grid.

7. A frequency control device comprising a thermionic tubehaving two grids, a plate, a reticulated plate, and an electron emitting element, an oscillating circuit in connection with one of said grids, said reticulated plate, and said electron emitting element, means for maintaining the oscillations of said circuit at a selected frequency, means for varying said selected frequency, and a second oscillating circuit in connection with the other of said grids, said plate, and said electron emitting element, said second oscillating circuit being tuned to oscillate at approximately a subharmonic of said first oscillating circuit, and said first and second oscillating circuits interacting through said tube to cause the oscillations of said second circuit to be at a frequency which is an exact sub-harmonic of the frequency of oscillations in said first circuit.

8. A frequency control circuit energized by a source of electrical energy and comprising an electron emitting element, a plate, a reticulated plate between said element and the first mentioned plate, a first grid between said reticulated plate and the first mentioned plate, a second grid between said reticulated plate and said electron emitting element, a vacuum envelope enclosing said plates, grids and electron emitting element, electrical conductor means extending between said electron emitting element and the negative side of the source of electrical energy, electrical conductor means 'extending between said reticulated plate and the positive side of such source of energy, means for impressing impulses of electrical potential upon said second grid at selected variable frequencies, electrical conductor means extending between the first grid and said electron emitting element, a first unit of inductance in series with the last mentioned electrical conductor means, electrical conductor means extending between the first mentioned plate and the positive side of the source of electrical energy comprising a second unit of inductance in series therewith coupled inductively with the first unit of inductance, said second unit of inductance being adapted in connection with said last mentioned conductor means for conducting impulses of electrical energy of a frequency corresponding to a selected sub-harmonic of the frequency of impression of potential upon said second grid, and means for varying the frequency of impression of potential upon said second grid.

9. A frequency control device comprising a thermionic tube having two'grids, a plate, a reticulated plate and an electron emitting element, an oscillating circuit in connection with one of said grids, said reticulated plate and said electron emitting element, a piezo-electric crystal for maintaining the oscillations of said circuit at a selected frequency, means for varying said selected frequency, and a. second oscillating circuit in connection with the other of said grids, said plate and said electron emitting element; said second circuit being tuned to oscillate at a frequency which is approximately a sub-harmonic of the frequency of oscillation of said first circuit, said first circuit coacting through said thermionic tube with said second circuit to cause the frequency of oscillation of said second circuit to be an exact sub-harmonic of the frequency of oscillations in said first circuit.

JAMES N. WHITAKER. 

